So, I've been talked into running an online game of savage worlds, play by post actually. This is new territory for me. Has anyone run or played in a SW online game? What are some pitfalls I should look out for? How do you handle cards with combat? How often should I refresh bennies?

I'm in several Savage Worlds games over on rpol.net and combat is pretty standard fair. The GM has the dice roller pull cards then assigns them. Usually post order isn't that big a deal, save for when the mooks/villains/baddies go, as this usually causes a pause as people do their thing, wait for the GM then the next group goes._________________"No man is so good as to be free from all evil,
nor so bad as to be worth nothing."

I too am preparing my first time GMing a Play-by-post game. But since I've played quite a few pbp games (no Savage Worlds game, but quite a few Deadlands), I can give some points:

Pitfalls:

Long Time in between posts - Sometimes real life things hinder posting, and the game can stall for a while. Stay patient. When I have to take off for something (guard drills, in my case), be polite and inform the GM and party you'll be away.

Post Bombs - I went to bed one night, and awoke to find twenty posts in play. Yeah, this is the opposite of the first problem. My suggestion is to read what happened, post your play. Maybe tell the other players to tone it down a bit, if you wish.

Players leaving - something I've seen every now and then is a player having to bow out due to some real life concern. What to do? Well, if everyone else is still game, game on. If someone else wants to step in, intro the new player in a logical manner and game on.

For Initiative cards, Strickland gave one option. What I was going to do was just grab a deck and deal the players in, then keep the deck available every combat round. Yeah, it's primitive and low-tech, but sometimes that's all you got.

Benny refresh, what I'm planning is to refresh after each "adventure" the party has. If it's really long, I'll break it up into sections, and once they hit each milestone, benny refresh.

I think the greatest pitfall is, really, that sometimes real life interferes and the game crawls to a halt.
This is just something that happens.

This can be especially annoying during combats. A couple of combat rounds can easily take a few weeks to resolve.
Don't be shy to take over a player if he hasn't posted in a few days. Post for him, let him take cover or something, move on.

Ask the players to tell you beforehand when they'll be out of town, so you know they'll be back after a two-week vacation and didn't just lose interest.

I've had a couple of players drop out and telling me beforehand - real life interfered or they simply didn't like the game.
Others simply disappeared. The latter group is harder to cope with, but if there's no reaction after a few weeks, I usually phase their characters out.

Since combats can take a while, I try to focus more on roleplaying. But of course, in Necropolis and cyberpunk - you can't just hang out in bars, sometimes you need to shoot at something and blow stuff up.

Thirdly, encourage players to be descriptive in their postings. It enhances the game a lot if everybody contributes to interesting scenes. If two players want to resolve something, for example - why should I, as GM dictate what the bar looks like where they meet?_________________Markus
The Sundered Skies Serial - full of spoilers!Savagepedia at wikispaces

I'm running a game on RPOL at the moment as well but we haven't had any combat yet. I've also run a few over at Rondak's years ago. I'm not sure where you intend on running yours but something I try to do on RPOL is check players log in times and make sure everyone has read my last post before making another reply. This I think will help with the post bombs mentioned earlier. Sometimes i'll answer in game questions directed to a NPC without waiting but that doesn't prevent anyone else from participating.

Just try to make sure everyone is having fun and be open to making changes if you have to to facilitate that.

I mean do you only write strictly what your character does i.e. actions others can see or is it generally ok to "fictionalize" your posts by writing stuff the other characters doesn't know about such as your characters inner dialogue/thoughts?

Let me share an example posts, even though it's totally out of context, it should give you some idea.

Samantha 'Doc' Smith wrote:

She throws a furious glance after Anton, still having the girls before her on their way to the door.
She turns to Nic "Are you out of your mind? What the hell were you thinking!?! Didn't I make clear that I wanted to have a low profile? Now I have the Russian Mob in my home, two drugged girls and you and John in I don't even know WHAT kind of B.S. ... Did you want to turn this place into a brothel, or what the heck was your intention?"She glances over the girls, who she hopes she made uncomfortable now - even though she knew that they probably were the least at fault. Where were those gals from in first place?

She turns back from Nic to John, her eyes sparkling with anger. "What now? Do you expect me to run around my own apartment with my gun in my pocket?
Nic... get rid of the girls, a cab should be waiting downstairs soon... And then I want to know what the <expletive deleted by me> you guys rode me into!"

I also encourage players to flesh out scenery - if it is common to be there (like a jukebox, tables and chairs in a bar) they can make it look like what they want and I add needed details. That way they can just post what they do when entering the example bar, without having to wait for me to post what it looks like first.

If the GM can handle the dice rolls it can make it go more quickly as well, although it does increase the GM workload.